Also called GI (gastrointestinal) tract because of the importance of the stomach and intestines

Digestive tract is __ feet long(in adult male)

27

(every part lined with mucus membrane)

Organs of the digestive tract

1.Mouth

2.Pharynx

3.Esophagus (diaphragm closes around)

4.Stomach (LUQ)

5.Small Intestines

6.Large Intestines

7.Anus

Accessory Organs of the Digestive System

1.Salivary Glands

2.Liver (RUQ)

3.Gall Bladder (tucked up underneath the liver)

4.Pancreas (epigastric area of abdomen)

Walls of the Digestive Tract

1.Mucous membrane lining

2.Connective Tissue Layer

3.Smooth muscle layer with two types of muscle action

a.local muscle contractions for mixing

b.peristalsis: wave-like muscle contractions that move "food" along the tract

4.outer layer of connective tissue

5.below diaphragm, the outer layer is instead the peritoneum, a 2 layered serous membrane covering over the organs of the abdominal and some of the organs of the pelvic cavity and lining the abdominal/pelvic cavities themselves.

Sections of the peritoneum anchor various organs in place

1.Anterior tissues

a.greater omentum

b.lesser omentum

2.Posterior tissues

a.mesentary

b.mesocolon

Mesentery

A double layered portion of the peritoneum shaped like a fan.

Attached to the posterior abdominal wall, and the expanded long edge is attached to the small intestine

Mesocolon

The section of the peritoneum that extends from the colon to the posterior abdominal wall.

Greater Omentum

A large double layer of the peritoneum containing much fat hangs like an apron over the front of the intestines.Extends from the lower border of the stomach into the pelvic cavity and then loops back up to the transverse colon.

Lesser Omentum

Smaller than the greater omentum, extends between the stomach and the liver

Functions of the Digestive Tract

1.Ingestion: process where "food" is taken into the mouth, chewed (mastication), and swallowed (deglutition)

2.Digestion: process where "food" is mechanically broken down and chemically split into different smaller substances

Proteins become amino acids

CHO become simple sugars

Fats become fatty acids and glycerol

3.Absorption: process where nutrients pass into the bloodstream (much of the fat in the form of fatty acids and glycerol goes into the lymph then into the bloodstream)

4.Elimination: process where undigested and unabsorbed "food" leaves the digestive tract by the process of defecation